This 5-year study is designed to investigate the effectiveness of a novel psychosocial intervention for children with ADHD, Family-School Success (FSS), that promotes collaborative problem solving between parents and teachers. The primary aim is to evaluate FSS in relation to a comparison group controlling for non-specific treatment factors (COMP) to determine its effects on educational and family functioning among children who are medicated as well as those who are unmedicated. Additional aims are to evaluate the intervention acceptability of FSS, and to explore the effects of potential moderators (e.g., comorbid internalizing disorder, ADHD subtype, gender, comorbid oppositional defiant disorder, learning disabilities, socioeconomic status) on treatment response. The sample will consist of 198 children in grades 2 through 6 who meet criteria for ADHD Combined and Inattentive Types. Participants will be randomly assigned to FSS or COMP. Families will be given a choice about whether their children will be on medication during the study; it is expected that 60% of the children will be medicated. The groups will be stratified according to medication status, comorbid internalizing disorders, oppositional defiant disorder, learning disabilities, ADHD subtype, and gender. Children whose families elect medication will receive open trials using a standardized protocol that prioritizes the use of long-acting stimulants. The experimental intervention (FSS) consists of three major components: (a) family-school behavioral consultation, (b) daily report cards with home-based reinforcement, and (c) targeted homework interventions using goal setting and contingency management strategies. Outcomes will be assessed at mid-treatment, post-treatment, and 6-month follow-up across four primary domains: homework performance, home behavior and parent-child interaction, school performance and behavior, and family involvement in education. Main effects (FSS versus COMP) and interaction effects (treatment group by medication status) will be evaluated using longitudinal, mixed effects models applied to the targeted outcome variables. Moderator and mediator effects will be evaluated using criteria outlined by Baron and Kenny. Mixed effects models will also be used to estimate the degree of treatment effect at the level of the individual child and family. [unreadable] [unreadable]